When transcendental devotional service, by which love for Krishna is attained is executed by the senses, it is called Saadhana Bhakti, or the regulative discharge of devotional service. Such devotion eternally exists within the heart of every living entity. The awakening of this eternal devotion is the potentiality of devotional service in practice. — Sri Caitanya Caritamrta, Madhya Lila, 22.105.
The three final instructions:- 1) Do not try to be a hero, simply try to be a speck in the hands of the spiritual master. 2) Always take shelter of Hari Naam & Hari Katha. 3) Beware of disunity.
Even in the books of patanjali yoga, it is said that in order to attain perfection in yoga one needs Hari-bhakti. Ultimately devotion is the perfection. Narayana Smriti at the end of one's life is perfection. Normally people end their life thinking of whatever their attached to. If we are chanting the Lord's names and engage in his service then we maintain an attachment for the Lord throughout our life. The Lord will be the common denominator and pivot point in our different activities. Whatever process one is engaging in, this remembrance of Narayana, taking shelter of the Lord is the most important aspect.
Pure devotion means that one is very eager and enthusiastic to serve the Lord at all time without any laziness.
The path of bhakti is personal, it is not ritualistically automatic.
Devotional service is so simple, but devotees because of their material inclinations make it complicated.